A seat belt system for use in a vehicle typically includes seat belt webbing, a seat belt retractor, and a seat belt buckle. A locking tongue on the webbing is releasably lockable in the buckle when the webbing has been extracted from the retractor and extended around a seated occupant of the vehicle. In some cases, the webbing extends through a D-ring which is mounted in the vehicle adjacent to the occupant's shoulder. Such a seat belt system may include a height adjuster for adjusting the height of the D-ring.
A seat belt system may further include a pretensioner which is actuated upon the occurrence of a vehicle crash. When the pretensioner is actuated, it imparts tension to the webbing to help the webbing restrain the vehicle occupant.